I signed up to the map update (6 new maps over 18 months) however, every time I try to update a map, it wipes the device and I end up having to contact customer support (which I have to say so far has been the only good thing about the Tomtom) It has happened four times now with the update before last causing the device to shut down completely and requiring me to send it back..

As others have said also, the latest map guarantee is meaningless and never up to date.